- ID:
- ivo://CDS.VizieR/J/A+A/338/340
- Title:
- Asteroids as IR Standards for ISOPHOT
- Short Name:
- J/A+A/338/340
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asteroids are used as far-IR calibrators for the imaging photopolarimeter ISOPHOT on board the Infrared Space Observatory ISO. For the 10 selected objects we compiled a large uniform database of 678 individual observations, ranging from 7-2000{mu}m. Applying a new thermophysical model to the observations we derived thermal properties of the selected asteroids, based on spin-vector solutions, direct size measurements and the HG-magnitude system. Our investigations indicate very rough surfaces, reflected in the beaming effect, and very low levels of heat conduction, expressed in thermal inertias between 5 and 25J/m^2^/s^0.5^/K. Due to scattering processes in the porous regolith, the emissivity varies significantly with wavelength. In case of Vesta we find emissivities as low as 0.6 in the far-IR/submillimetre region. By entering the combined results into the thermophysical model we defined new photometric standards for the far-IR. The absolute accuracy for thermal flux or lightcurve predictions is 5-10% for the first category objects and 10-20% for the secondaries. The methods and procedures discussed here are included in the first update of the ISOPHOT calibration in 1998.
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- ID:
- ivo://CDS.VizieR/J/AJ/161/78
- Title:
- Astrometry for 14 debris disk stars with SPHERE
- Short Name:
- J/AJ/161/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Debris disk stars are good targets for high-contrast imaging searches for planetary systems, since debris disks have been shown to have a tentative correlation with giant planets. We selected 20 stars identified as debris disk hosts by the WISE mission, with particularly high levels of warm dust. We observed these with the VLT/SPHERE high-contrast imaging instrument with the goal of finding planets and imaging the disks in scattered light. Our survey reaches a median 5{sigma} sensitivity of 10.4MJ at 25au and 5.9MJ at 100au. We identified three new stellar companions (HD18378B, HD19257B, and HD133778B): two are mid-M-type stars and one is a late-K or early-M star. Three additional stars have very widely separated stellar companions (all at >2000au) identified in the Gaia catalog. The stars hosting the three SPHERE-identified companions are all older (>~700Myr), with one having recently left the main sequence and one a giant star. We infer that the high volumes of dust observed around these stars has been caused by a recent collision between the planets and planetesimal belts in the system, although for the most evolved star, mass loss could also be responsible for the infrared excess. Future mid-infrared spectroscopy or polarimetric imaging may allow the positions and spatial extent of these dust belts to be constrained, thereby providing evidence as to the true cause of the elevated levels of dust around these old systems. None of the disks in this survey is resolved in scattered light.
- ID:
- ivo://CDS.VizieR/J/PASJ/63/S1
- Title:
- Atlas and catalog of dark clouds based on 2MASS
- Short Name:
- J/PASJ/63/S1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents an atlas and catalog of dark clouds derived based on the 2 Micron All Sky Survey Point Source Catalog (2MASS PSC). Color excess maps of E(J-H) and E(H-K_S_) as well as extinction maps of A_J_, A_H_, and A_K_S_ covering all of the sky have been produced at the 1' grid with a changing angular resolution (~1'-12'), depending on the regions in the sky. Maps drawn at the lower 15' grid with a fixed 1{deg} resolution were also derived for various sets of threshold magnitudes in the J, H, and K_S_ bands to estimate the background star colors and star densities needed to derive the color excess and extinction maps. The maps obtained in this work are presented on various scales in a series of figures that can be used as an atlas of dark clouds for general research purposes. On the basis of the E(J-H) and A_J_ maps drawn at the 1' grid, we have carried out a systematic survey for dark clouds all over the sky. In total, we identified 7614 dark clouds, and measured the coordinates, extents, and A_V_ values for each of them. We also searched for their counterparts in a previously published catalog of dark clouds based on the optical photographic plates DSS (Dobashi et al., 2005PASJ...57S...1D, Cat. VII/244). These cloud parameters, including the information of the counterparts, are compiled into a new catalog of dark clouds.
- ID:
- ivo://CDS.VizieR/J/ApJ/824/29
- Title:
- ATLASGAL clumps with IRAS flux and MALT90 data
- Short Name:
- J/ApJ/824/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a survey of 65 galaxies, Gao & Solomon (2004ApJS..152...63G) found a tight linear relation between the infrared luminosity (L_IR_, a proxy for the star formation rate) and the HCN(1-0) luminosity (L_HCN_). Wu et al. (2005ApJ...635L.173W) found that this relation extends from these galaxies to the much less luminous Galactic molecular high-mass star-forming clumps (~1pc scales), and posited that there exists a characteristic ratio L_IR_/L_HCN_ for high-mass star-forming clumps. The Gao-Solomon relation for galaxies could then be explained as a summation of large numbers of high-mass star-forming clumps, resulting in the same L_IR_/L_HCN_ ratio for galaxies. We test this explanation and other possible origins of the Gao-Solomon relation using high-density tracers (including HCN(1-0), N_2_H^+^(1-0), HCO^+^(1-0), HNC(1-0), HC_3_N(10-9), and C_2_H(1-0)) for ~300 Galactic clumps from the Millimetre Astronomy Legacy Team 90GHz (MALT90) survey. The MALT90 data show that the Gao-Solomon relation in galaxies cannot be satisfactorily explained by the blending of large numbers of high-mass clumps in the telescope beam. Not only do the clumps have a large scatter in the L_IR_/L_HCN_ ratio, but also far too many high-mass clumps are required to account for the Galactic IR and HCN luminosities. We suggest that the scatter in the L_IR_/L_HCN_ ratio converges to the scatter of the Gao-Solomon relation at some size-scale >~1kpc. We suggest that the Gao-Solomon relation could instead result from of a universal large-scale star formation efficiency, initial mass function, core mass function, and clump mass function.
- ID:
- ivo://CDS.VizieR/J/ApJS/107/281
- Title:
- Atlas of hot, luminous stars at 2 microns
- Short Name:
- J/ApJS/107/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 2um (K band) spectra of 180 well-studied, optically visible, luminous stars. Most of the stars are of OB spectral type, but we have also included a number of Oe and Be stars, OBN and OBC stars, cool hypergiant stars, and high-mass X-ray binary stars. Our aim in studying normal OB stars is to develop an empirical relationship between 2um spectral features of these massive stars and their stellar temperature and luminosity. We find the system of lines between 2.0 and 2.2um is particulary good for differentiating the early- and mid-O type stars. In the late-O and early-B stars, differentiation becomes more difficult, as the features show only moderate changes. We have developed a spectral classification system for the K band to be used to estimate effective temperatures of O and early-B stars. We demonstrate that K-band spectroscopy is superior in estimating the temperature of hot, luminous stars than the traditional methods of using infrared or even optical photometric colors alone. The only requirements are that adequate resolution (R>1000) and signal-to-noise (S/N~70) be achieved. With our classification system, stars behind large amounts of visible extinction, such as young, heavily reddened H II regions throughout our Galaxy, may be identified and studied for the first time through 2um spectroscopy. Emission lines are commonly seen in the K-band spectra of supergiant stars, however, the OBN supergiants, which have a higher ratio of some processed materials at their surface, may be more likely to show line emission, especially the He I singlet transition at 2.058um. This has led us to propose an evolutionary scenario for some of the Galactic center He I emission-line stars, which evokes rotational mixing (Maeder 1987A&A...178..159M; Langer 1992A&A...265L..17L) to explain both the strong line emission and high luminosity of these mysterious sources. We have compared our spectroscopic database with the most recent stellar atmosphere models. We are encouraged by the good match between the model line profiles at 2um of Schaerer et al. (1996A&A...312..475S) and those observed in OB stars. Finally, we include a thorough discussion of the observational and reduction methods employed to obtain the spectra shown in this atlas for the benefit of those wishing to obtain similar, classification-quality, near-infrared spectra.
- ID:
- ivo://CDS.VizieR/III/217
- Title:
- Atlas of 840-880nm spectral region
- Short Name:
- III/217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This Atlas illustrates the behavior of stars of all spectral types in the near infrared 8400-8800 Angstrom spectral region with a resolution of about one Angstrom. The spectra have been obtained at the Observatoire de Haute-Provence at a dispersion of 33{AA}/mm. A total of 130 spectra (76 of early-type stars published in Paper I, and 54 of late-type stars published in Paper II) are available. They cover the spectral range O to M and different luminosity classes. The Atlas includes also spectra of stars with spectral peculiarities: 19 from Paper I and 11 from Paper II.
- ID:
- ivo://CDS.VizieR/III/183
- Title:
- Atlas of 837.5-877nm spectral region I.
- Short Name:
- III/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/ApJS/95/1
- Title:
- Atlas of Quasar Energy Distributions
- Short Name:
- J/ApJS/95/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an atlas of the spectral energy distributions (SEDs) of normal, non-blazar, quasars over the whole available range (radio to 10 keV X-rays) of the electromagnetic spectrum. The primary (UVSX) sample includes 47 quasars for which the spectral energy distributions include X-ray spectral indices and UV data. Of these, 29 are radio quiet, and 18 are radio loud. The SEDs are presented both in figures and in tabular form, with additional tabular material published on CD-ROM. Previously unpublished observational data for a second set of quasars excluded from the primary sample are also tabulated. The effects of host galaxy starlight contamination and foreground extinction on the UVSX sample are considered and the sample is used to investigate the range of SED properties. Of course, the properties we derive are influenced strongly by the selection effects induced by quasar discovery techniques. We derive the mean energy distribution (MED) for radio-loud and radio-quiet objects and present the bolometric corrections derived from it. We note, however, that the dispersion about this mean is large (~one decade for both the infrared and ultraviolet components when the MED is normalized at the near-infrared inflection). At least part of the dispersion in the ultraviolet may be due to time variability, but this is unlikely to be important in the infrared. The existence of such a large dispersion indicates that the MED reflects only some of the properties of quasars and so should be used only with caution.
- ID:
- ivo://CDS.VizieR/J/A+A/416/655
- Title:
- Atomic lines in IR spectra for ultracool dwarfs
- Short Name:
- J/A+A/416/655
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide a set of atomic lines which are suitable for the description of ultracool dwarf spectra from 10000 to 25000{AA}. This atomic linelist was made using both synthetic spectra calculations and existing atlases of infrared spectra of Arcturus and Sunspot umbra. We present plots which show the comparison of synthetic spectra and observed Arcturus and Sunspot umbral spectra for all atomic lines likely to be observable in high resolution infrared spectra.
- ID:
- ivo://CDS.VizieR/J/ApJ/764/133
- Title:
- Auriga-California giant molecular cloud
- Short Name:
- J/ApJ/764/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have mapped the Auriga/California molecular cloud with the Herschel PACS and SPIRE cameras and the Bolocam 1.1mm camera on the Caltech Submillimeter Observatory with the eventual goal of quantifying the star formation and cloud structure in this giant molecular cloud (GMC) that is comparable in size and mass to the Orion GMC, but which appears to be forming far fewer stars. We have tabulated 60 compact 70/160 {mu}m sources that are likely pre-main-sequence objects and correlated those with Spitzer and WISE mid-IR sources. At 1.1 mm, we find 18 cold, compact sources and discuss their properties. The most important result from this part of our study is that we find a modest number of additional compact young objects beyond those identified at shorter wavelengths with Spitzer.
